Atomic % and weight %

1. Nov 11, 2011

somebodyelse5

1. The problem statement, all variables and given/known data
Given: 5x10^21 Phosphorous atoms/m^3 in solid solution in silicon

Find: atomic percent and weight percent of Phosphorous atoms

3. The attempt at a solution
I know how to solve for at. % and wt. % when given two values, I am not sure how to get the second value given the mixture is a "solid solution"

Do i have enough information to solve this?

Solid solution means that it is completely mixed, but how would that lead me to a density of silicon that I could used to solve for at.% and wt.%?

2. Nov 11, 2011

wukunlin

phosphorous in silicon...

this sounds like semiconductor doping to me
without any other information given I would assume this is the case, therefore I would decide the density of silicon by its cell structure and lattice parameter

3. Nov 11, 2011

Staff: Mentor

Or just take density from any reliable source listing densities of elements. Amount of P is low enough to not change the density substantially.

4. Nov 11, 2011

somebodyelse5

My book has nothing to do with "Doping" and my class has not covered this. My book actually, does not even cover at. % or wt. %.

So I could just look up the density of silicon in as a solid and calc from there? Temperature does not matter here? (assuming that it doesn't, since the problem does not say)

5. Nov 12, 2011

Staff: Mentor

Temperature doesn't matter - much. Density of solids doesn't change significantly with temperature (doesn't mean it doesn't change at all).

6. Nov 12, 2011

somebodyelse5

thanks guys, looks like i just made this problem a bit more difficult than it had to be. I am going to use a density in g/cm^3 and convert it to atoms/m^2 and calculate at.% and wt. % from there.